Qhov sib txawv tseem ceeb ntawm kev hloov pauv thiab kev hloov pauv yog qhov kev hloov pauv yog hloov cov lus teeb liab los ntawm kev ntxiv nws nrog cov teeb liab cab kuj thaum demodulation yog cov txheej txheem ntawm kev lim tawm cov xov tooj tiag tiag ntawm lub teeb liab.
Feem ntau, lub xov tooj cua xa xov tooj cua tsim tawm ntawm sab kis ntawm kev sib txuas lus sib txuas lus. Hauv kev sib kis, nws yog ib qho tsim nyog yuav tsum xa cov teeb liab mus rau qhov ntev. Feem ntau, lub teeb liab zaus muaj peev xwm taug kev mus ntev. Yog li ntawd, cov lus ceeb toom los yog cov ntaub ntawv teeb liab ua ke nrog lub teeb liab zaus hu ua lub teeb liab cab kuj tsis cuam tshuam rau nws cov yam ntxwv qub. Cov txheej txheem ntawm kev sib txuas cov lus teeb liab nrog lub teeb liab cov cab kuj hu ua kev hloov kho. Cov txheej txheem demodulation tshwm sim ntawm qhov kawg tau txais.
Modulation yog dab tsi?
Modulation yog tus txheej txheem ntawm kev tso cov ntaub ntawv uas peb xav tau hloov mus rau hauv lub teeb liab nqa khoom. IEEE txhais cov kev hloov pauv raws li "tus txheej txheem uas qee yam ntawm cov nthwv dej, feem ntau hu ua tus cab kuj, muaj ntau yam lossis xaiv raws li qhov kev hloov pauv."
Muaj ntau hom kev hloov kho. Nyob rau hauv Amplitude Modulation (AM) lub amplitude ntawm lub teeb liab carrier sib txawv raws li qhov amplitude ntawm cov lus teeb liab. Frequency Modulation (FM) hloov cov teeb liab zaus raws li cov lus qhia. Phase Modulation (PM) hloov cov cab kuj theem raws li cov lus qhia.
Daim duab 01: Kev Sib Txuas Lus
Digital Modulation hloov pauv cov cim analog rau cov ntawv digital ntawm 1s thiab 0s. Muaj ntau yam kev hloov kho digital. Amplitude Shift Keying (ASK) sawv cev rau binary cov ntaub ntawv nyob rau hauv daim ntawv ntawm variations nyob rau hauv lub amplitude ntawm lub teeb liab. Frequency Shift Keying (FSK) hloov qhov zaus ntawm cov teeb liab nqa khoom raws li qhov kev hloov pauv digital. Phase Shift Keying (PSK) hloov cov theem ntawm cov teeb liab cov cab kuj los ntawm kev sib txawv ntawm sine thiab cosine inputs ntawm lub sijhawm tshwj xeeb.
Kev hloov pauv ntawm sine waveform tso cai rau hloov pauv cov lus qhia hauv qab rau hauv lub teeb liab passband; Piv txwv li, lub suab qis qis rau hauv lub xov tooj cua zaus (RF teeb liab). Hauv xov tooj cua tshaj tawm xov tooj cua thiab lub suab sib txuas lus, lub tswv yim no tau siv ntau heev los hloov lub suab ntawm lub suab hauv lub suab mus rau hauv ib qho passband channel.
Demodulation yog dab tsi?
Demodulation yog tus txheej txheem ntawm kev rho tawm cov ntaub ntawv teeb liab los ntawm lub teeb liab nqa khoom. Cov txheej txheem demodulation yuav tsum tau ua raws nraim nrog cov qauv kev hloov pauv, txwv tsis pub, qhov kawg ntawm qhov kawg yuav tsis tuaj yeem rho tawm cov ntaub ntawv tseem ceeb ntawm lub teeb liab ntawm cov cab kuj. Yog li ntawd, thawj zaug sib tuav tes yuav tsum muaj nyob rau hauv ib tug tsim nyog mechanism los tham txog cov modulation thiab demodulation txoj kev ua ntej, rau ib tug dynamic ib puag ncig.
Piv txwv li, hauv kev sib txuas lus hauv xov tooj, cov kev hloov pauv tuaj yeem hloov pauv sai. Yog li ntawd, kev sib tuav tes yuav siv qhov chaw ua ntej hloov ntawm ib txoj hauv kev mus rau lwm qhov lossis siv cov algorithms tshwj xeeb ntawm qhov chaw kawg kom rho tawm cov ntaub ntawv los ntawm kev txheeb xyuas cov qauv kev hloov pauv qub. Txhua txoj kev hloov kho, xws li AM, FM, PM thiab lwm yam. muaj lawv tus kheej demodulation txoj kev kom rov qab tau cov teeb liab qub ntawm qhov chaw kawg.
Cov khoom siv uas ua ob qho tib si kev hloov pauv thiab demodulation yog hu ua modem. Modulation thiab demodulation txheej txheem feem ntau yog tsom mus rau kev xa cov ntaub ntawv nrog qhov tsawg kawg nkaus distortion los yog kev noj nyiaj txiag, qhov tsawg kawg nkaus poob rau cov teeb liab nqa, thiab siv tau zoo ntawm cov spectrum. Txawm hais tias muaj ntau txoj hauv kev los yog cov txheej txheem rau kev hloov kho thiab cov txheej txheem demodulation, lawv muaj lawv tus kheej qhov zoo thiab qhov tsis zoo. Piv txwv li, AM yog siv nyob rau hauv luv luv thiab nruab nrab yoj xov tooj cua tshaj tawm, FM yog siv nyob rau hauv Heev High Frequency (VHF) xov tooj cua tshaj tawm, thiab PM yog nrov nrog cov teeb liab modulation.
Qhov txawv ntawm Modulation thiab Demodulation yog dab tsi?
Modulation yog tus txheej txheem ntawm impinging cov ntaub ntawv tseem ceeb ntawm lub teeb liab cov cab kuj, thaum demodulation yog rov qab los ntawm thawj cov ntaub ntawv los ntawm lub teeb liab cov cab kuj. Feem ntau, kev hloov pauv tshwm sim ntawm lub transmitter thaum demodulation tshwm sim ntawm tus txais.
Summary – Modulation vs Demodulation
Qhov txawv ntawm qhov kev hloov kho thiab kev hloov pauv yog qhov kev hloov pauv yog hloov cov lus teeb liab los ntawm kev ntxiv nws nrog cov teeb liab cab kuj thaum demodulation yog cov txheej txheem ntawm kev lim tawm cov xov tooj tiag tiag los ntawm cov teeb liab cab kuj. Ob qho tib si modulation thiab demodulation txheej txheem yog qhov tseem ceeb sib npaug rau kev hloov cov ntaub ntawv teeb liab siv lub teeb liab nqa. Yog li ntawd, txoj kev hloov kho peb siv ntawm lub transmitter yuav tsum tau ua raws nraim nrog txoj kev demodulation ntawm tus txais qhov kawg kom ua tiav cov ntaub ntawv hloov pauv ntawm ib qho chaw mus rau lwm qhov.
